Motion picture camera

ABSTRACT

THE TAKEUP REEL OF A MOTION PICTURE CAMERA IS ROTATED BY WAY OF THE CLAW PULLDOWN. THE CONNECTION BETWEEN THE PULLDOWN AND THE REEL COMPRISES A PAIR OF MESHING GEARS ONE OF WHICH IS CONNECTED WITH THE REEL, A TWO-ARMED LEVER ONE ARM OF WHICH IS ROCKED BY THE PULLDOWN BY WAY OF A TORSION SPRING AND THE OTHER ARM OF WHICH CARRIES TWO PAWLS. ONE PAWL IS DISENGAGED FROM ONE OF THE GEARS WHEN THE OTHER PAWL ROTATES THE OTHER GEAR, AND VICE VERSA, WHEREBY THE REEL ROTATES IN A SINGLE DIRECTION.

Dec. 11, 1973 wm ETAL Re. 27,839

MOTION PICTURE CAMERA Original Filed March 17. 1969 IN VEN T015FRIEDRICH WINKLER BY KURT THATE United States Patent 27,839 MOTIONPICTURE CAMERA Friedrich Winkler, Unterhaching, and Kurt Thate,

Munich, Germany, assignors to Agfa-Gevaert Aktiengesellschaft,Leverkuseu, Germany Original No. 3,570,783, dated Mar. 16, 1971, Ser.No. 808,385, Mar. 17, 1969. Application for reissue Feb. 29, 1972, Ser.No. 230,530 Claims priority, application Germany, Mar. 28, 1968, P 17 72083.1 Int. Cl. Bllh 15/32; G03b N04 US. Cl. 242-205 23 Claims Matterenclosed in heavy brackets [1 appears in the original patent but formsno part of this reissue specification; matter printed in italicsindicates the additions made by reissue.

ABSTRACT OF THE DISCLOSURE The takeup reel of a motion picture camera isrotated by way of the claw pulldown. The connection between the pulldownand the reel comprises a pair of meshing gears one of which is connectedwith the reel, a two-armed lever one arm of which is rocked by thepulldown by way of a torsion spring and the other arm of which carriestwo pawls. One pawl is disengaged from one of the gears when the otherpawl rotates the other gear, and vice versa, whereby the reel rotates ina single direction.

CROSS-REFERENCE TO RELATED CASE This is a reissue of our Pat. No.3,570,783, granted M10216, 1971.

BACKGROUND OF THE INVENTION The present invention relates tophotographic apparatus in general, and more particularly to improvementsin motion picture cameras, especially [in] 8-millimeter motion picturecameras. Still more particularly, the invention relates to improvementsin film transporting mechanisms for motion picture cameras.

In a motion picture camera, a motor normally drives a claw pulldownwhich transports film stepwise past the film gate. The motor also drivesthe takeup reel which collects the film at a point remote from the clawpulldown. As a rule, the takeup reel receives [a] rotary motion by wayof a worm and worm wheel. A drawback of such film transportingmechanisms is that the efficiency of worm drives is very low and thattheir manufacturing cost is high. Furthermore, the operative connectionbetween the worm drive and the takeup reel must include a frictioncoupling which permits the takeup reel to remain at a standstill whilethe motor continues to operate the worm drive when the entire film iscollected by the takeup reel. This insures that the film does not tearor that its trailing end is not disconnected from the supply reel. Thefriction coupling must be constructed and mounted with a high degree ofaccuracy to insure that it produces a constant friction. This isnormally achieved by employing a friction coupling with several axiallyaligned elements which are in frictional engagement with each other.Such assembly of the coupling insures that at least one pair offrictionally engaged elements offers a predetermined resistance tomovement of one element with reference to the other element even if thecoupling undergoes considerable wear. Alternatively, the couplingcomprises one or more adjustable springs which must be adjusted fromtime to time by qualified workmen to compensate for wear.

SUMMARY OF THE INVENTION An object of [out] our invention is to providea film transporting mechanism wherein the power train between the motorand the takeup reel need not include a worm drive and/ or a frictioncoupling.

Another object of the invention is to provide a motion transmittingmechanism which can be operated by exertion of a smaller force thanpresently known mechanisms.

A further object of the invention is to provide a film transportingmechanism which is more compact, simpler and less expensive than themechanisms of presently known motion picture cameras.

An additional object of the invention is to provide a film transportingmechanism which can be installed in presently known types of motionpicture cameras.

The improved film transporting mechanism comprises a first gear which isdrivingly connected with a film collecting member, preferably a takeupreel, and meshes with a second gear, and means for alternatinglyrotating the gears in opposite directions so that the film collectingmember is driven in a single direction, either directly by the firstgear or by the second gear through the intermediary of the first gear.The means for rotating the gears in opposite directions preferablycomprises a pair of pawls and means for moving one of the pawls intorotary motion transmitting engagement with one of the gears when theother pawl is disengaged from the other gear, and vice versa. The meansfor moving the pawls preferably comprises a two-armed lever one arm ofwhich carries the pawls and the other arm of which receives rockingmotion from the output shaft of the motor, for example, by way of thecustomary claw pulldown and by interposition of a resilient element.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved film transporting mechanism itself, however, both as to itsconstruction and its mode of operation, together with additionalfeatures and advantages thereof, will be best understood upon perusal ofthe following detailed description of certain specific embodiments withreference to the accompanying drawmg.

BRIEF DESCRIPTION OF THE DRAWING The single figure is a schematic [and]end elevational view of a film transporting mechanism which is installedin a motion picture camera and embodies our invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawing shows a portion ofan electric motor 1 which is installed in the housing or body of amotion picture camera, preferably an 8-millimeter camera. The outputshaft 1a of the motor carries a gear 2 in mesh with a gear 3 mounted onan intermediate shaft 3a which is journaled in a wall 3b forming part ofthe camera body. The shaft 3a carries a second gear 4 which is coaxialwith the gear 3 and drives a larger gear 5 mounted on a shaft 5a whichis journaled in a wall 5b. The gear 5 rotates an eccentric drivingmember 5c which reciprocates a claw pulldown 8. The latter has a claw 8bwhich can enter the perforations 22 of a film 21 to move the filmstepwise past the film gate, not shown. It will be seen that the geartrain 2, 3, 4, 5 and the eccentric 5c from part of a first power trainwhich reciprocates the pulldown 8. A second power train which derivesmotion from the first power train or from the pulldown 8 is employed torotate the shaft 11 of a film collecting or takeup reel 11a and theshutter (not shown). This second power train includes the following:

The shaft 11 of the takeup reel 11a is connected with a first gear 13which meshes with a second gear 12 on a shaft 10. The diameters of thegears 12, 13 are the same. The shaft 11 should rotate in a clockwisedirection in order to convolute the film 21 onto the takeup reel 11a.This is achieved by rotating the gear 13 in a clockwise direction by wayof a first pawl 14a or by rotating the gear 12 in a counterclockwisedirection by way of a second pawl 14b. The pawls 14a, 14b are pivotablymounted on the right-hand arm of a two-armed lever 15 which is mountedon a pivot pin 15c and receives motion from the claw pulldown 8 by wayof a torsion spring 18. It will be [see] seen that the parts 15, 14a,14b, 18 constitute a device for converting reciprocatory movements ofthe pulldown 8 into intermittent rotary movements of the shaft 11. Thepawls 14a, 14b are coupled to each other by a helical spring 17 whichtends to hold them in the illustrated positions. The pivot member 15c ismounted in the housing of the camera and the lever 15 has a largecentral portion or hub 16 which supports the convoluted part 18c of thetorsion spring 18. The left-hand arm of the lever 15 is provided withtwo stops 15a, 15b, for the legs 18a, 18b of the torsion spring 18. Thetips of the legs 18a, 18b straddle a motion transmitting projection orlug 8a of the claw pulldown 8.

The operation:

The drawing shows the pulldown 8 in a position in which its claw 8bstill extends into a perforation 22 of the film 21. The eccentric 5c hascompleted movement of the pulldown 8 in the direction indicated by arrow20. During such [the pulldown] movement of the pulldown 8, the legs 18a,18b caused the lever to turn in a counterclockwise direction whereby thepawl 14a caused the gear 13 to rotate the shaft 11 and takeup reel 11ain a clockwise direction. When the pulldown reaches the lower end of itsstroke, as viewed in the drawing, its claw 8b is caused to leave theperforation 22 and the eccentric 5c then moves the pulldown 8 upwardly,i.e., counter to the direction indicated by arrow 20. This causes theprojection 8a and the legs 18a, 18b to pivot the lever 15 in a clockwisedirection whereby the pawl 14b rotates the gear 12 in a counterclockwisedirection. Since the gear 12 meshes the gear 13, the shaft 11 and takeupreel 11a are caused to rotate in a clockwise direction, namely, in thesame direction as when the pawl 14a drives the gear 13. The pawl 14a isdisengaged from the teeth of the gear 13 when the pulldown 8 reaches itslower end position and the pawl 14b is disengaged from the gear 12 whenthe pulldown reaches its upper end position. The pawl 14a engages withthe teeth of gear 13 when the pawl 14b is disengaged from the teeth ofgear 12, and vice versa. The takeup reel 11a is always rotated in theclockwise direction, regardless of whether the pulldown 8 moves up ordown, as viewed in the drawing.

An important advantage of our film transporting mechanism is that thecamera which embodies such mechanism need not employ a worm drive whichis standard part of many presently known motion picture cameras. Also,the improved film transporting mechanism can dispense with manyadditional parts which are needed in the driving connection between themotor and the takeup reel of a conventional camera. The efliciency of aworm wheel drive (as regards the transmission of forces) is veryunsatisfactory, and the cost of a power train which employs a worm driveand one or more additional gears is much higher than the cost of thepower train which includes the parts 15, 18, 14a, 14b and 12, 13.Another important advantage of the improved film transporting mechanismis that it need not employ a friction coupling between the shaft 11 andthe takeup reel 11a or between the shaft 11 and the gear 13. Suchfriction couplings are absolutely necessary in nearly all types ofpresently known film transporting mechanisms. We omit the frictioncoupling if the convoluted part 18c of the spring 18 simply slips on thehub 16 of the lever 15 when the film 21 is fully collected by the takeupreel 11a. At the present time, we prefer to design the legs 18a, 18b ofthe spring 18 in such a way that they yield sufiiciently when the filmis collected by the reel 11a. The legs 18a, 18b then continue to movewith the projection 8a but the lever 15 remains at a standstill.

It is clear that the improved film transporting mechanism is susceptibleof many modifications without departing from the spirit of ourinvention. For example, the reel 11a can be mounted on the shaft 10 ofthe gear 12. Also, the spring 18 need not be moved by the projection 8aof the pulldown 8 because the mechanism can include a second eccentricwhich is driven by the output shaft 1a or by one of the shafts 3a, 5aand reciprocates a member which performs reciprocatory movements similarto those of the pulldown 8. Such reciprocable member then transmitsmotion to the lever 15 by way of the spring 18 or by way of an analogousresilent motion transmitting element.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that other can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of our contribution to the art.

We claim:

1. In a film transporting mechanism for motion picture cameras, acombination comprising a rotary film collecting member; a first geardrivingly connected with said film collecting member; a second gearmeshing with said first gear; and means for alternatingly rotating saidgears in opposite directions so that said film collecting member isdriven in a single direction, comprising a pair of pawls and means formoving one of said pawls into a motion transmitting engagement with oneof said gears when the other pawl is disengaged from the other gear, andvice versa, said means for moving said pawls comprising a lever which isrockable about a fixed axis and comprises an arm pivotably supportingsaid pawls, means for rocking said lever, and resilient means yieldablycoupling said pawls to each other.

2. In a film transporting mechanism for motion picture cameras, acombination comprising a rotary film collecting member; a first geardrivingly connected with said film collecting member; a second gearmeshing with said first gear; and means for alternatingly rotating saidgears in opposite directions so that said film collecting member isdriven in a single direction, comprising a pair of pawls and means formoving one of said pawls into rotary motion transmitting engagement withone of said gears when the other pawl is disengaged from the other gear,and vice versa, said means for moving said pawls comprising a leverwhich is rockable about a fixed axis and comprises an arm supportingsaid pawls, and a reciprocable claw pulldown for rocking said lever.

3. A combination as defined in claim 2, wherein the means for rockingsaid lever further comprises motion transmitting means yieldablyconnecting said lever to said claw pulldown.

4. A combination as defined in claim 3, wherein said motion transmittingmeans comprises resilient means arranged to yield in response toreciprocation of said claw pulldown when said lever encounters apredetermined resistance to rocking movement about said axis.

5. A combination as defined in claim 4, wherein said resilient meanscomprises a torsion spring.

6. A combination as defined in claim 5, wherein said lever comprises asecond arm and wherein said torsion spring comprises a coiled portionsurrounding said axis and two elongated legs, said second arm of thelever being provided with stop means for said legs and said pulldowncomprising a motion transmitting projection which is flanked by saidlegs.

7. In a film transporting mechanism for motion picture cameras, acombination comprising a rotary film collecting member, a first geardrivingly connected with said film collecting member; a second gearmeshing with said first gear; and means for alternatingly rotating saidgears in opposite directions so that said film collecting member isdriven in a single direction, comprising a pair of pawls and means formoving one of said pawls into rotary motion transmitting engagement withone of said gears when the other pawl is disengaged from the other gear,and vice versa, said means for moving said pawls comprising a leverwhich is rockable about a fixed axis and comprises an arm supportingsaid pawls, and an eccentric for rocking said lever.

8. A combination as defined in claim 7, wherein the means for rockingsaid lever further comprises a member which is reciprocated by saideccentric and transmits rocking motion to said lever.

9. A combination as defined in claim 7, wherein said first gearcomprises a shaft and wherein said film collecting member is a takeupreel which is driven by said shaft.

10. In a film transporting mechanism for motion picture cameras, acombination comprising a rotary film collecting member; a first geardrivingly connected with said film collecting member; a second gearmeshing with said first gear; a claw pulldown arranged to transportstepwise a portion of film which is remote from said collecting member;a motor having a rotary output member; a first power train connectingsaid pulldown with said output member and arranged to reciprocate saidpulldown; and means for alternatingly rotating said gears in oppositedirections so that said film collecting member is driven in a singledirection, comprising a second power train which receives motion fromsaid output member.

11. A combination as defined in claim 10, wherein said second powertrain derives motion from said output member by way of said clawpulldown.

12. A combination as defined in claim 10, wherein said second powertrain derives motion from said output member by way of saidfirst-mentioned power train.

13. In a film transporting mechanism for motion picture cameras, acombination comprising a rotary film collecting member; a first rotarydriven element drivingly connected with said film collecting member; asecond rotary driven element cooperating with said first driven elementto rotate in a second direction when said first driven element isrotated in a first direction and to drive said first element in saidfirst direction when driven to rotate in said second direction; andmeans for alternatingly driving said first and second driven elements insaid first and second directions, respectively, so that the filmcollecting member is rotated in a single direction, comprising a pair ofdriving elements and means for moving one of said driving elements intodriving engagement with said first driven element when the other drivingelement is disengaged from the other driven element, and vice versa,said means for moving said driving elements comprising a carrier whichis [workable] rotatable about a predetermined axis and supports saiddriving elements, and a claw pulldown for rocking said carrier.

14. In a film transporting mechanism for motion picture cameras, acombination comprising a rotary film collecting member, a first rotarydriven element drivingly connected with said film collecting member; asecond rotary driven element cooperating with said first driven elementto rotate in a second direction when said first element is driven torotate in a first direction, and to rotate said first element in saidfirst direction when driven to rotate in said second direction; andmeans for alternatingly driving said first and second driven elements insaid first and second directions, respectively, so that the filmcollecting member is rotated in a single direction, comprising a pair ofdriving elements and means for moving one of said driving elements intodriving engagement with one of said driven elements to rotate said onedriven element in the respective direction when the other drivingelement is disengaged from the other [driving] driven element, and viceversa, said means for moving said driving element comprising a carrierwhich is rockable about a predetermined axis and supports said drivingmembers, and eccentric means for rocking said carrier.

15. In a film transporting mechanism for motion picture cameras, acombination comprising a rotary film collecting member; rotary torquetransmitting means operatively connected with said film collectingmember to rotate the latter in a single direction; and means forrotating said torque transmitting means, comprising first and seconddriving elements, carrier means pivotable alternatingly about apredetermined axis in first and second directions and supporting saiddriving elements, and motor-driven film feeder means operable to pivotsaid carrier means, said first and second driving elements beingrespectively arranged to rotate said torque transmitting means inresponse to pivoting of said carrier means in said first and seconddirections.

16. A combination as defined in claim 15, wherein said torquetransmitting means comprises toothed gear means and said drivingelements are pawls which cooperate with the teeth of said gear means torotate said film collecting member in said single direction in responseto pivoting of said carrier means.

17. A combination as defined in claim 15, further comprising resilientmotion transmitting means interposed between said carrier means and saidfilm feeder means.

18. A combination as defined in claim 17, wherein said resilient motiontransmitting means comprises a torsion spring in frictional engagementwith one of said film feeder and carrier means.

19. A combination as defined in claim I 5, wherein said carrier meanscomprises first and second portions both remote from said predeterminedaxis, said driving elements being provided on said first portion andfurther comprising resilient motion transmitting means interposedbetween said film feeder means and said second portion of said carriermeans.

20. A combination as defined in claim 15, wherein said driving elementsare movable relative to said carrier means and relative to each other,and further comprising resilient means for yieldably maintaining saiddriving elements in predetermined positions relative to said carriermeans.

21. A combination as defined in claim 15, wherein said film feeder meansand said driving elements are angularly spaced from each other relativeto said predetermined axis.

22. A combination as defined in claim 15, wherein said film feeder meanscomprises a reciprocable portion and further comprising resilient motiontransmitting means for converting the reciprocatory movement of saidportion of said film feeder means into pivotal movement of said carriermeans.

23. A combination as defined in claim 15, further comprising resilientmotion transmitting means interposed between said feeder means and saidcarrier means to per mit movements of said feeder means independently ofsaid carrier means when said film collecting member offers apredetermined resistance to rotation in said single direction.

References Cited The following references, cited by the Examiner, are

of record in the patented file of this patent or the original patent.

UNITED STATES PATENTS 1,351,938 9/1920 Allen 74-443 2,135,026 11/1938Becker 242-205 LEONARD D. CHRISTIAN, Primary Examiner US. Cl. X.R. 7488,143

